The field of the present invention is the art of U-bolt saddle clamps that are employed for holding sections of tubing in telescoped connection or securing together cable sections which are generally referred to as U-bolt clamps or saddle clamps. Such devices are frequently employed in the exhaust systems of automotive vehicles powered by internal combustion engines.
The prior art directly concerned with such clamps is, for the most part, derived from a basic assembly comprising a U-bolt having a semicircular bight portion integrally connecting a pair of generally parallel legs which are threaded on their ends and which are received in axially slidable relation within a sheet steel saddle member having tubular portions receiving and housing the bolt legs and connected by a central web extending transversely between the tubular housings and integral therewith. The free threaded ends of the legs receive nuts that are tightened up against the tubular portions of the saddle member to clamp together a joint of telescoped tubes, such as for example, an exhaust joint disposed between the bight of the U-bolt and the curved edge of the saddle member.
In recent years exhaust system gas-tightness and mechanical security requirements have been amplified by governmental pollutant standards, stimulating the development of stronger and more effective clamp designs.
One widely used U-bolt clamp proven capable of dealing with present industry requirements in millions of automotive and truck installations, is noted in Heckethorn U.S. Pat. No. 3,955,250. An equally effective, lighter duty clamp is exemplified by pending Heckethorn application Ser. No. 796,217, filed May 12, 1977. The above clamps are currently produced in sizes 1.5 inches through 6.0 inches.
A new requirement has recently developed in the automotive industry for joining and sealing very small stainless steel tubing, used for exhaust gas recirculation and exhaust gas air injection systems.
Prior art U-bolt clamps made in accordance with Heckethorn U.S. Pat. 3,955,250 are, of necessity, larger in diameter than the tubing to which they are applied. When tightened sufficiently to form a gas-tight locking bead, the tubing is somewhat out of round. On tubing joints within the normal 1.5 inch to 6.0 inch range this out of roundness is of little concern. On very small tubing joints of, for instance 7/8 inch diameter, the out of roundness is both noticeable and harmful from a gas flow and leakage standpoint.
The U-bolt clamp of the present invention has an internal diameter substantially smaller than the outside diameter of the tubing joint to which it is applied. An extremely uniform bead is formed 360.degree. about the joint, assuring perfect roundness, gas tightness and mechanical security. The saddle portion of the clamp is reinforced preferably to prevent web twist to give greater strength and stability, as in my copending application noted above.
The invention consists in the novel design of both the saddle member and the U-bolt portion to permit for the first time in the art the coupling together of pipe members having an outside diameter that is actually larger than the internal diameter of the assembled and closed U-bolt clamp.